Fuel feed control



lJuly 16, 193s. F. MDCK 008,143A

FUEL FEED CONTROL Filed Jun'e 22, 1951 4 sheet-sneet 1 INVENTOR 27m/mir?C Moc/ ATTORNEY July 16,1935- F. c. MocK 2,008,143

` FUEL FEED CONTROL u Filed June 22. 1931 4 Sheets-Sheet 2 :.@FllllllllATTORNEY Julyls, 1935. f FQMOCK 2,008,143

- FUEL FEED CONTROL Filed June 22, 1931 4 sheets-sheet s 237 c n m l c fi. l E INVENTOR a ,.95 M C/Vocl I L A A ,a7 BY' A ATroRNEY A July 16,1935.

F. C. MOCK FUEL FEED CONTROL Filed June 272, 1931 4 Sheets-Sheet '4 IN VEN TOR.

Han/f C. Moc/r ATTORNEY.

Patented July 16, 1935 UMTEDA STATESY FUEL FEED CONTROL Frank C. Mock,Montclair, N. J., assignor to Bendix Research Corporation, East Orange,N. J., a corporation of Indiana Application June 22, 1931, serial No.546,122

48 Claims.

The invention relates generally to fuel-feeding systems or apparatusfor'internal combustion engines, and more especially to novel andimproved Vmeans or systems for supplying liquid fuel to the air chargeby pressure positively applied to the fuel, in distinction fromcarbureting the intake air in a carburetor. A principal use contemplatedis in connection with engines of types in which the mixture is formedexternally of the cylinder, and is ignited by spark, in distinction fromcompression-heat ignition, although the mode of ignition per se does notaffect the invention-devices.

Although not limited to such uses, the invention .is especially valuablein application to aircraft engines, wherein the problem of properlymetering fuel delivered by pump or like action to the intake air at apoint anterior to the combustion chamber, is greatly complicated by theair pressure variations caused by changes in elevation of the aircraftfrom sea level to high altitudes, as Well as by air pressure variationsin the mixing space or manifold caused by changes of throttle position,both yof which factors affeet the weight of the air charge in differentWays, as will appear.

The general object of. the invention is to supply to such engines underthe varying operating conditions, a mixture of combustible proportions,to maintain the air-fuel ratio approximatelyA constant when so desired,and/or to vary the proportions as is desirable under certain conditions.

Typical suction operated carburetors have the capacity to proportion themixture approximately satisfactorily under the various air-serviceconditions; but in the absence of a suctionoperated carburetor and withpump or analogous fuel supply, an inventive problem is involved inpractically controlling the air-fuel proportion. Y

A principal object of the invention is to provide 4o in fuel supplysystems of the character defined,

fuel proportioning means which will operate automatically and keep themixture approximately uniform, and/or to vary the proportions within thedesired ranges in some cases, thus largely or entirely relieving theoperator of the necessity to arbitrarily manipulate or readjust the fuelmechanism while flying, and making this general mode of fuel supplycommercially practical. i

In a system of the stated character, in attempting to automaticallycontrol the fuel supply, in the absence of a corburetor and theinherenicapacity of air flowingthrough such an instrument to take upfuel in approximately proper proportions, it is necessary to utilizeother forces than air-flow to effect fuel proportioning.; and a prin-(Cl. 12S-F75) is effected or affected by an instrumentality responsiveto pressure in the mixing space or mixture duct between the throttle andthe engine; i. e., as commonly expressed, in the manifold". Also, insome cases, these principal controlling methods or means may be employedcooperatively.l In some cases, also, the instrumentality which isresponsive to pressure in the mixing space may be, at the same time,more or less directly responsive to external atmospheric pressure.

In some cases, also, the apparatus or system may include, in addition toone or more such pressure-responsive instrumentalities, means of moremechanical character, which may cooperate with or modify the action ofsuch pressureresponsive, or pneumatic means. An example of such amechanical instrumentality is a device vpositioned by variations inthrottle setting and connected more or -less directly in a mechanicalsense to the fuel-supply-regulating element, and which is itself actedupon, or cooperates with, a pressure-responsive instrumentality toaffect the position of thev fuel-controlling element.

In some preferred forms, a principal feature of the invention consistsin a novel and improved fuel-supply apparatus, including a continuouslyfeeding or non-metering pump, fuel chambers, and fuel-'flow controlmeans constructed and arranged to maintain a desired high fuel feedpressure and at the same time to meter the flow to the mixing space ator in an orifice which is subjected at its opposite ends to a fuelpressure difference of a relatively or definitely small amount, thusproviding high injection pressure with a 10W metering pressure; or, inother Words, it is thus possible to provide a metering orifice andneedle valve of substantial diameters which can practicably be producedwith necessary accuracy; Whereas when the full supply pressure, of theorder, for example, of four hundred pounds per square inch, is appliedto the metering orifice, in order to keep the total flow down to thenecessary maximum, the orifice must be extremely small and the needlevalve of correspondingly small size and delicate character, so thatpractical commercial production is diflicult and expensive, orimpossible.

This fuel supply apparatus, while especially applicable 4to fuel supplyregulating systems of present character, is not limited yto such uses,'but is evidently available,with or without modification, in a greatvariety of cases where fuel is to be supplied under more or lessanalogous conditions, against substantial back pressure; as, forexample, that afforded by the spring of an injection valve, or byinternal pressure in the vessel or chamber into which the fuel isintroduced.

The invention is based largely upon determination, by study andexperiment, of the fact that in an engine of the subject character,variation in the weight of the air charge caused by altitude variationis at a different ratio from that caused by variations in the throttleopening; and in devising means or apparatus to effect the desiredcontrol of fuel, in certain of the preferred forms, as here disclosed,such means or elements are designed to act responsively to both of thesevariation ratios in a. manner to provide a substantially uniformmixture, or when desired, also to vary the fuel proportion substantiallyunder certain conditions, as will appear.

While a principal utility of the invention is in connection withaircraft engines, it is also applicable to engines of other types orthose used for other purposes, too numerous toy mention, but some ofwhich are briefly referred to hereinafter.

The characteristics and advantages of the invention are furthersufficiently referred to in connection with the following detaildescription of the accompanying drawings, which represent certainpreferred embodiments. After considering these examples, v'skilledpersons will understand that many variations may be made withoutdeparting from the principles disclosed; and I contemplate theemployment of any structures, arrangements, or modes of operation thatare properly Within the scope of the appended claims.

Fig. 1 is partly in elevation and partly in section, and also ofsomewhat diagrammatic character, showing certain sufficientappurtenancesof an internal combustion engine and elements included in the invention,as embodied inone preferred form.'

Fig. 2 is a similar View of a modified structure or arrangement. y

Fig. 3 is a similar view of another modification.

Fig. 4 is a diagram explanatory of the principles of air-charge weightvariation, previously referred to. l

Figs. 5 and 6 are diagrams for explanation of pressure conditions in aconventional engine and its intake passage.

Fig. 7 illustrates a modification of the oonstruction or arrangement ofthe barometric device of Fig. 1.4

Fig. 8 is a View similar to Fig. l, illustrating,

' however, important Variations or modifications adjustment of theaneroid of Fig. 1.

Fig. 10 is a view in elevati-on showing a modified throttle control.

The principles of construction and operat-ion of the invention deviceswill be better understood after rst considering some of the fundamentalsof pressure variation causing charge weight variations.

When fuel supply`means such, for example, as a displacement type ofpump, is employe-d, which can bemade to give equal fuel charges percylinder when thoe engine speed is varied, it is preferred in accordancewith the invention to coordinate the fuel pump delivery per charge withthe pressure of the air in the intake manifold beyond the throttle,because when this pressure is constant the air charge per cylinder isalso approximately constant at different engine speeds at constanaltitude.l

Referring first to a simple engine with conventional carburetor, fuelsupply and throttle, as illustrated in Fig. 5, where the piston is aboutto start its suction stroke, with the throttle valve l entirely closed,before the intake valve 3 opens, the combustion space 5 is filled withgas which was equalized, during the previous opening of the exhaustvalve, to approximately atmospheric pressure. After the intake valveopens, this exhaust gas lls both the cylinder and its combustion space,and the intake manifold 'l between the throttle and the intake valve,lso that, as shown in Fig. 6 with no air (or a negligible amount)entering the intake passage, the pressure in the intake manifold will beto atmosphere as the volume of the gas space in Fig. 5 is to. that inFig. 6 (temperature effects being disregarded). i

Therefore, referring to Fig. 4 if at sea level there is a full aircharge corresponding to the point a, that is, 30 Hg. absolute pressure,-there will be a zero air charge with the throttle entirely closed, asindicated at a', and the pressure corresponding to any fractional aircharge will be shown by the line a-a'. This is found to hold truethrough quite a large range of speeds, although the actual value of amay vary between 281/2" and 30, and of a' between l0" i and 12,depending on the individual characteristics of the engine and intakesystem. If the engine be `taken to an altitudejwhere the air is rarer,approximately the same ratio holds true for throttling; for instance, ata. level Where the external pressure is b, or 20 Hg., (disregardingtemperature), the air charge at full throttle opening will be 20/30 ofthat at sea level. If the throttle be closed entirely, the intakepressure will be 1l /3Q of 20, or 7.3 Hg. as shown at b, and therelation of air charge to the absolute pressure will be' shown by theline b-b. On the other hand, if the throttle be held full open as thealtitude and air pressure around the engine are changed, the relation ofair 'charge weight to the pressure in the manifold is direct, as shownby the line a-b-jo.

As otherwise stated, the invention may be said to depend, in certain ofits principal aspects, upon the following theory, which is statedlargely for convenience of explanation and understanding of o-perationof the invention structure, although dependence is not necessarilyplaced upon correctness of this or other theoretical explanations hereincontained:

In an ordinary aircraft engine, assuming it to have a simple main airintake opening, a throttle 1 in the air line, and a mixture space(manifold or the like) between the throttle and the engine,-

vary the charge weight at a constant rate. The total force available forcontrolling fuel supply rate by utilization of pneumatic pressure, inaccordance with the invention, is the difference between normal pressureat sea level and hypothetical zero pressure (as if the engine could beflown above atmosphere, or obtainable by placing the engine in a vacuumchamber).

The charge Weight variations caused by throttling are effective in themanifold or equivalent chamber between the throttle and the engine, ator from which general location these pressure variations are utilized inthe invention to effect a fuel control appropriate to these variations.The total force exerted or available at the stated location for thestated purpose has not a range from zero to the maximum obtainable byaltitude variation, namely, 30" Hg. absolute, but this range commencesat a minimum which is approximately 11" Hg. with fully closed throttleat sea level and, of course, with zero air charge, this minimum withclosed throttle decreasing with increase of altitude; and from thestated varying minimum, the range of variation of course runs to themaximum available at full throttle opening, that is 30" Hg. absolute atsea level, and decreasing to zero at some hypothetical altitude or in avacuum.

It thus appears that the force available for fuel adjustment by altitudedirectly varies in a simple ratio, while that available for adjustmentin accordance with throttling varies in a more complex ratio; that is,the manifold pressure variation may be said to be simple at eachaltitude, and for any throttle setting the manifold variation withrespect to different altitudes is also simple, but the combined ratiowhich is effective under iiying conditions on account of continualchanges in elevation and variations in throttle setting, is quitecomplex.

In certain of the preferred practical embodiments, in order to obtainoptimum advantages of the invention, the fuel adjustment is affected bya first device directly responsive` to external atmosphere, and at thesame time the adjustment is effected by a second device which isprimarily responsive to the manifold pressure, and without furtherprovision will, in coordination with the first-named device, attain afuel adjustment which is fairly accurate and satisfactory in' 'alllcases. If preferred, the secondnamed device r'nay be made at the sametime responsive to Adirect atmospheric pressure, thus introducing intofuel'adjustment by this second device what may be called a correctionfor altitude; and when the two devices, having characteristicsas laststated, are coordinated, the fueladjustment accuracy is very close tothe severest practical requirements.

In some cases, the system organization may include, in addition to otheritems mentioned 'previously to the preceding theoretical explanation, asupercharger, or supercharging blower,

delivering its -output to the air supply passage in advance of thethrottle, thus creating in the air passage at this point, that is,between the main supercharger and the throttle, a pressure aboveatmosphere, which may be considered for the 'present purpose as anartificial atmosphere anterior to the throttle; and irr the just statedsystem organization, this pressure is momentarily 'applied in lieu ofthe actual atmospheric pressure to effect the desired fuel regulation;or, in other words, the fuel adjustment is in this case made inaccordance with a pressure equal to atmosphereplus, the plusrepresenting the additional pressure to to the supercharger.

Some or all of the previously'stated facts or principles are utilizedina practical way for the invention purposes in the structuresdisclosed, of which Fig. 1 shows a preferred form, representing anembodiment of the nature just above discussed in general terms; that is,one having an instrumentality responsive directly to atmosphericpressure and another instrumentality responsive .to manifold pressureand also to atmospheric pressure, although the latter function may insome cases vbe eliminated; 'and these instrumentalities are arranged tocontrol the fuel supply adjusting device.

As here shown, a main air intake duct or pipe 9 leads to a rotarydistributor or' supercharger I2 of an internal combustion engine which,Ias here sufliciently illustrated, is of a radial aircraft type. Theintake air passage 9 contains the throttle I I .which is operated by arod I3 extending from the pilots cockpit. The pilot thus controlsdirectly the air charge of the engine while the fuel charge, as will bedescribed in detail, is automatically controlled by the engine speed (orintake manifold pressure as eifected by the throttle opening and speed)and/or by altitude. Insome cases, as further referred to below, a mainsupercharger or supercharging blower may be employed to supply air athigher'than atmospheric pressure to the air passage leading to thethrottle; and in such cases an instrumentality such as the rotarydistributor I2 just above mentioned, if used, will generally be employedprincipally as a distributor or fuel mixer.

The invention structure as shown in Fig. 1 and elsewhere is associatedwith a radial aircraft engine, since its advantages are fully utilizedin such an adaptation. An instrumentality such as the blower I2 is notessential to the invention, but is here shown as representing approvedpractice in aircraft engines, and serves to or assists in atomizing andproperly distributing fuel introduced into the air line in the mannerpresently referred to. The blower discharges' into a generally annularchamber I 5 from which pipes lead to the intake parts of the variouscylinders, as usual in this type of engine.-

A yieldable device such as I'I is desirably interposed in the manualthrottle control as described in detail below.

It is to be understood that the entire air passage between the throttleand the engine heads represents broadly an intake manifold, and thepneumatic connectionI for fuel control in accordance with throttlepositioning is at a convenient point in this manifold or air spacebetween the throttle and the engine proper.

Any known or suitable fuel pump I9 is provided. As illustrated, thispump is of a known form, details of the pump structure beingunimportant, except as'presently mentioned. Fuel is supplied to the pumpat 2I and is delivered from it through a pipe 23 to an injection orificeor nozzle 25 in the air conduit arranged to deliver the fuel to theintake of the blower I2, in accordance with the selected fuel-supply,mixing andv distributing arrangement although obviously it may beinjected into the engine at any other desired point. In the pump areplungers 21 operated by bell cranks 29 and the bell cranks are actuatedby a tapered sliding cam 3l mounted on a `shaft 33 which is driven inany suitable way, the drive arrangement shown being typical and itsdetails immaterial to the invention. The vertical positioning of the camvaries the stroke of the bell cranks and of the plungers 21 and thusregulates the pump charge per revolution of the engine. In a broadsense, this represents any suitable mode of regulating the amount offuel, or the rate at which fuel is supplied to the mixing point at asuitable pressure.

The cam 3| is operated by means such as a lever structure in any mannersuitable to the purposes of the invention, and in some cases a simplelever, linkage or like mechanism may be employed. As shown, the cam ispositioned principally by a lever structure which involves severalelements, mainly for the purpose of obtaining variations in chargeproportioning, as will appear; although the cam control can be greatlysimplified if it is sufficient to maintain substantially uniform mixtureproportions. The stated mechanism includes a lever 35 -fulcrumed at 31in casingl part and having a fork 39 engaging in a shifting channel 4|on the camand also having an adjustable stop screw 43 engaging a fixedstop 45 to establish minimum-charge position of the cam. At a convenientposition, as shown, adiacent the pump, is a fixed frame or supportingstructure including a casing 41 forv purposes below mentioned. On a partof this frame or casing structure is fulcrurned a leve-r mechanism 49having three arms 5|, 53, and 55. A secondary or floating lever 51 (socalled for convenient reference) is fulcrumed at 59 on lever arm 55. Thefloating or auxiliary lever has: a stop member or lug 6| cooperatingwith a shoulder or stop member 63 on lever arm 55 and is urged in adirection such that the lug 6 I engages the shoulder 63 by a spring 65acting between an extension of 61 of lever arm 55 and lever 51. Thefloating lever also desirably has la member or extension 69(conveniently called a toe) to cooperate with a fixed abutment such as apart of the casing 41. The outward end of lever 35 is connected by alink 1| tothe inward end of lever 51.

In casing 41 is any known or suitable pneumatic-pressure-responsivedevice of the general nature of a barometric element or aneroid. As

shown, this device 13 is an axially-extensible sheet metal bellows ofknown form, and evacuated to a desired degree, so that it tends tocontract. This element is conveniently referred to in some cases as anevacuated aneroid. The contractile tendency of this element is resisted,or

' in other words it is normally elongated, by suitable means such as aspring 15. In a convenient physical arrangement, one end of the aneroidelement has an extension 11 with a. ball fitting 19 engaging in a socketin the casing end and enclosed, if necessary, by a cap 8|. The other endof the element has an extension 83, and to one end of this extension,one end of the spring 15 is connected, while the other end of the springmay have an adjustable connection to the casing end, as by a screw 85which engages in the casing Wall. The spring is calibrated and/oradjusted to its maximum, while the atmospheric pressure always tends tocompress or shorten the aneroid. These movements are communicated tolever arm 53 so that, disregarding any other forces tending to effectthe stated movements and also for the present disregarding the floatinglever 51, the movements of the aneroid element caused by altitudevariations act through lever 35 to position cam 3| in such mannerthat,as the pressure applied to 'the aneroid increases, (as when thecraft is descending), the aneroid is compressed and the lever mechanismoperates to move the cam 3| downward on its shaft, thus increasing thestroke of the pump plungers and the amount o1' fuel delivered into theintake air, the fuel supply being of course decreased as the craftrises; and when the various factors of design are correct the air-fuelratio is maintained substantially constant, so far as correction forelevation alone is concerned.

Additional control, in accordance with throttle positioning is alsoprovided in accordance with Fig. 1, as follows: In a convenientlocation, which may be on casing 41, a pneumatic chamber 9| is provided,having at one face a exible diaphragm 93 of a suitable diameter, thechamber being in this instance sealed except for a connection through apipe 95 to the mixing space or manifold at 91; that is, as previouslyreferred to, this connection is made at some suitable point in the airline between the throttle and the engine heads. .The chamber 9| and itsdiaphragm 93 or equivalent element, represent broadly any known orsuitable instrumentality responsive to pneumatic pressure and which isby the pipe connection 95 made responsive to the pressure in themanifold. This instrumentality, or at least a part of it,

in the present example subjected and responsive to an extent largelycontrollable by factors of design, to atmospheric pressure, since itsouter face is directly exposed to atmosphere. r1`he movable element ofthis second pneumatic instrument, namely, the diaphragm 93, isconnected, as by a pin or stud 99 and pivot |0| to the end of the arm 5|of the three-armed lever previously mentioned.

This second pressure responsive instrument such as 93, disregarding forthe present the aneroid element 13, tends to and will position lever arm55, lever 35, and cam 3|,.in accordance with pressure variations in themanifold at the point 91, in such manner that the delivery4 of the pumpper revolution is decreased as the pressure in the manifold decreasesor, as more accurately stated with reference to this particulararrangement, fuel delivery is decreased in accordance with the pressuredifference between the manifold and external air.

When the two pressure-responsive instrumentalities are connected in themanner shown and described, so that both act upon the lever arm 55, itis apparent without lengthy repetition of previous explanation ofoperative characteristics, that the cam 3|, and therefore the amount offuel delivered, is regulated mutually by the two pressure-responsivedevices, in accordance with all the conditions connected with altitudeand throttle position, to maintain a substantially constant mixture'proportion; so that, to give a single example, if the pressure in themanifoldZ is brought from the point a of Fig. 4 corresponding to 30" Hg.with full open throttle at sea level, to a pressure of 20 Hg., byclosing the throttle, the air charge will be brought to the namely thediaphragm 93 or equivalent, is also will be regulated solely by thepressure differential acting to expand aneroid 13. Further, if thesurrounding air pressure be brought to the point c, or 25" Hg. bychanging the altitude, and then the pressure in the intake passage bebrought to Hg. corresponding to the point c', by closing the throttle,the change in air charge will bring the two sets of pressure values tobear on the mechanical controlling elements, one represented by thevalue ndue to increased altitude, and the other represented by the valuem, due to the result of closing the throttle; these two, m and ncombined, being in the same proportion to the air charge as would beobtained, first by getting this first air charge weight at sea level byclosing the throttle vsufficiently to produce a manifold pressure of16.7 Hg., or second, by leaving the throttle wide open and going to analtitude of 9 pressure.

There is thus secured auniform mixture proportioning of fuel and air.Actually, it is desirable in many cases to increase the richness lof themixture slightly -as the air charge is decreased, which may beaccomplished by varying the effective action of diaphragm 93 (orequivalent element) in relation to the strength lof spring '15. For thispurpose, for example, the area of the diaphragm may be Varied, orspecifically, made smaller than is required .for practically uniformproportioning. The result of this is equivalent, with reference to thediagram, to changing the slope of the line a-a.

It is also desirable in many-cases to increase the richness of themixture at from about 28"v to 30" Hg. absolute pressure, because underthese high air charge weights the engine tends to overheat, and a richermixture assists in cooling it. This effect is obtained in the describedstructure by the floating lever 5'I and its appurtenances, the action ofwhich has heretofore been disregarded. Through most of the range ofmove.

movement ofthe main lever arm; or, in other words, multiplies the upwardmovement of connecting link 1| and provides the desired increase in theproportion of fuel to air.

It will now also be apparent' that, while the inventionvin this form,providing what may be called the full fuel mixture proportion controlcontemplated by the invention, has been de'- scribed asapplied to andacting in cooperation with an aircraft engine ,'and with such an engineof a more or less specialized type, it is evidently applicable toaircraft engines of other types or to various internal combustionengines used for other purposes, although of course its greatest utilitywill be with an engine subjected to considerable variations of speed andload, as well as altitude; so that the invention is applicable, forexample, to vehicle engines where the vehicle is driven in mountainouscountry, and where heretofore fuel control in relation to altitude hasbeen absent or of a rudimentary character, and

there has been notablev lack of efciency in land vehicles` when requiredto climb to high altitudes.

With reference to this usage, the invention by including pump orequivalent fuel supply in combination with a blower or the like, whichmay have a supercharging action, and suitable fuel controlling devicesaccurately responsive to speed and load variations as well as altitudevariations, will greatly increase the utility and eflciency of a landvehicle in mountainous country.

Fig. 8 shows a modification based largely on the fundamentals involvedin Fig. 1, as above discussed, but including in the 'air supply system asupercharger or supercharging blower which supplies its output to theair conduit 9 at some convenient point anterior to the throttle Il. Inthis case a device similar to the rotary distributor I 2 of Fig. 1 mayalso 'be .employed when desirable or necessary and, when equal tosurrounding atmosphere plus the addedpressure produced by the action ofthe blower at the moment. It will now be evident that this articialatmospheric pressure may be utilized for the invention purposes in thesame general manner that actual atmospheric pressure is utilized in theexample of Fig. l, to obtain the desired fuel regulation with respect toaltitude. The pressure-responsive means or devices are in the case ofFig. 8 associated with or contained in a casing |05 which may beconsidered a sealed `casing except forpneumatic-pressure-connectionopenings to be mentioned. Thepressure-responsive device |01 substantially similar tothe device I3 ofFig. 1 is arranged in substantially the same manner, being connected at|09 to a lever arm I II fulcrumed on a shaft I |3 which passes outthrough a casing wall (withsuitable packing, not necessary toillustrate) and has outside the casing an arm I I5 operativelyequivalent to the lever arm 55 of Fig. 1, and other devices affording amechanical connection to lever 35, in order to position afuel-regulating member such as the cam 3| of Fig. 1, in accordance withthe movements of arm H5. Also mounted and sealed at an aperture in thecasing is a diaphragm the inner face of which is subjected to thepressure condition existing in the casing and the outer face is enclosedby cap I I9 forming a pneumatic chamber |2| The diaphragm is connectedas by a stem |23 to an extension of leverarm I I I.

A further extension of this lever arm is also engaged by' a spring |25,which acts between it and the main interior space of the casing ||l5 andthus to the barometric device |01 in such manner that increase ofpressure tends to collapse it against the effort of spring |25, whichtends to extend it.

At the same time, this artificial atmosphere pressure, oratmosphere-plus pressure, is applied to the inward face of the diaphragm||1 while through the pneumatic conduit |3|, manifold pressure isapplied to the outward face of the diaphragm, thus practicallyreproducing the operative characteristics of Fig. 1 except that in thisinstance the altitude control takes into account in a proper manner theaction or effect of the supercharger located or arranged in the system,as here shown.

Fig. 2 shows a modification of the invention structure, involving insome respects a simplification and also introducing what I havehereinabove referred to as a mechanical controlling instrumentality ormeans, in cooperation with pressure-responsive means.

In this arrangement the pump, pump cam and cam-controlling lever areoperated by a single aneroid responsive to b oth manifold pressure andaltitude changes, while the link |33 operating lever 35 is itselfarranged to be operated as an incident to the movement of the throttleI, thus providing the before-mentioned mechanical controlling feature.Specifically, as here shown, a fixed structure or frame, hererepresented by a casing |35, has an arm |31 to which is fulcrumed atone. end a lever |39 normally urged upward by a spring |4 and having aroll or follower |42 cooperating with a cam |43 on the throttle shaft|45. The lever has a cam face |41 of suitable design, and this isengaged by a roll or cam follower |49 at the lower end of link |33, andwhen necessary .a spring |5| may be applied at a suitable place, as tolink |33, tending to retain the roll |49 in contact with the cam |41,andat the same time to normally maintain the pump cam 3 in upwardposition. In the casing |35 is located a pressure-responsiveinstrumentality |53 substantially similar to evacuated aneroid 13 ofFig. 1, and this is connected by any suitable means such as a rock-lever|55 fulcrumed at |51, to a rod |59 which reciprocates in the casingwall. This lever is connected by a link |6| to link |33, conveniently atits lower end. A spring |63 is applied in a manner tending normally tomove the cam follower |49 to the right, al viewed in the drawings, andalso tending to extend or expand the aneroid element.

This mechanism is capable by simple modifications or rearrangements tooperate in different manners, for example, the aneroidA |53may in somecases be exposed to external atmospheric pressure, as by providing anaperture in the casing |35, and will then tend to effect a fueladjustment in accordance with altitude variations or the like.Otherwise, and as specially illustrated, the casing may be connected tothe external atmosphere by a restricted opening |65, and also through apipe |61 to the manifold or intake passage at a point 91; that is, apneumatic connection located as in Fig. l; the relative sizes of theopenings |65 and passage being so chosen that a change of manifoldpressure exerts the same force upon the aneroid |53 as woulda change ofaltitude giving the same manifold air density. Thus, it is responsive tochanges of both throttle position and altitude; and in either case,'when pressure applied to the aneroid increases, it tends to contractand to move the cam follower |49 to the left, as viewed in Fig. 2, withthe result, so

' long as the throttle is in stationary position, that link |33 is movedupward and the pump, cam 3| is moved downward, increasing the fuelsupply; and when pressure decreases the aneroid expands, and spring |63moves the follower |49 in the opposite direction, causing a decrease infuel supply.

Further, as a minor control, when the throttle is moved toward openposition by rod |3 acting on arm |69, spring |4| moves the outward endof lever |39 upward to an extent permitted by the positioning of the cam|43, thus moving link |33 and lever 35 in a direction to increase thefuel supply; and similarly, in the closing movement of the throttle thefuel supply may be decreased through this mechanical means. At the sametime the action of the aneroid element |53 or the equivalent pneumaticcontrol, in either of the cases referred to, positions the follower |49in relation to the cam element |41, thus effecting a fuel regulation inaccordance with both throttle position and a pressure condition, whichmay be one controlled by altitude or by throttle position.

Fig. 3 shows the generall principles so far explained, embodied in adifferent form. Especially this embodiment includes in place of apositive feeding or metering pump of the character heretofore described,a novel and improved fuel supply means including a continuously-feedingnonmetering pump |1|, an injection valve |13 controlled by a spring |15and arranged to deliver fuel into the mixing space or manifoldsubstantially at the point described with reference to Figs. 1 and 2;that is, axially toward the inlet of a rotary charge distributor, bloweror supercharger, and fuel-controlling and metering means |11 of thecharacter referred to early above, having as a principal characteristicand advantage the capacity to meter the fuel at low pressure (or at alow pressure-differential), while the necessary high pressure ismaintained in the pipe line leading to the injecting valve |13; that isto say, while the fuel pressure actually existing in the neighborhood ofthe metering orice and valve is high (of the order, in some cases, of400 pounds per square inch, more or less), the difference in pressuresat opposite ends of the metering orifice is comparatively small andactually may be very small, say of the order of about five pounds, (moreor less) with the advantages sufficiently referred to previously.

The fuel controlling means comprises a casing |19 divided by a diaphragm|8| into a lower chamber |83 'and an upper chamber |85. The pump |1|,which may be of any known or suitable type, providing substantiallycontinuous supply at a suitable pressure, has an intake passage |81 anda discharge passage or fitting |89 leading to the lower chamber |83. Theupper chamber |85 is connected by a pipe |9 |.to the' injection valve|13. The lower chamber |83 has a port |93 and connected thereat areturn-flow or lay-pass pipe |95 leading to the intake pipe |81 adjacentthe pump. At the inner end of the port |93 is a valve seat |91 withwhich cooperates a valve |99 connected to the diaphragm |8|. This valveis loaded by a spring 20| compressed between its upper end or thefitting connecting it to the diaphragm, and a spring retaining cap 203screwed into the top casing wall.

The meteringV aperture is located in an operative sense between theupper and lower chambers. Specifically, as shown, this aperture 205 isin the end of a sleeve 201 inserted into the casing wall, and terminatesin the lower chamber, while the vsleeve is apertured to communicate withthe passage formation 209 in the casing, affording communication fromthe metering aperture. to the upper chamber |85. The metering valve 2||reciprocates in the sleeve 201, packing such as 2|3 being provided as inanalogous structures. This valve is positioned, to secure fuelregulation, in a mannerdescribed below.

The pump |1| suppliesfuel to the lower chamber |83 at a rate greaterthan is required for engine consumption, the excess being returned tothe supply pipe |81 through port |93 and bypass pipe under control ofvalve |99. The

control spring 20| of valve |99 is in practice, in one good example, setto open at about 400 pounds pressure and to maintain about the samepressure as the delivery of fuel increases. This puts approximately thesame pressure on the fuel in pipe |9| and in the upper diaphragm chamber|85. The loading spring 20| is designed or ad-l justed to place asuitably determined pressure on the valve, say approximately fivepounds, more or less. The result is that the system tends to Vmaintain apressure of approximately 400 pounds per square inch in the upperdiaphragm chamber, pipe |9I, and passages leading` to the 'injectionvalve, together with substantially-continuous fuel-flow, whenconsumption-conditions so permit or demand; and a substantially thoughonly moderately greater pressure, namely, approximately 405 pounds,- inthe lower diaphragm chamthe `parts may be produced with necessary ac-`curacy on a commercial basis.

This fuel supply system may of course be used in any of the forms of theinvention, such as shown4 in Figs.I 1 and 2, the various fuel controldevices' being in such case arranged to act on metering valve 2||instead of on the fuel-pump driving cam.- v i As suggested early above,this fuel supply means may be used for various other purposes, such forexample as supplying fuel to injector valves of Diesel engines or thoseof analogous types, or in various other cases where the fuel is to bedischarged against valveor internal-pressure-resistance.

In the embodiment of Fig. 3, there is provided a mechanical fuel controland also a pressure-responsive control. The mechanical control, asshown, comprises a cam 2|3 on the shaft of throttle acting upon afollower 2|5 carried by a lever 2|1 fulcrumed at a fixed point 2|9. Thefree end of this lever is connected by a link 22| or equivalent means toact upon the metering valve 2| A pressure-responsive instrumentality223, which may be a sealed or evacuated aneroid similar to thosepreviously referred to, is enclosed in a fixed casing 225 and has a stem221 passing through the casing, with a spring 229 arranged to actbetween the casing and the stem and tending to expand the aneroid. Thestem is also connected to a lever 23| fulcrumed at 233 on a xed support,and the lever is connected as through a link 235 to act upon themetering valve The lever mechanism' for operating the metering valve 2|I, as here shown, comprises a lever consisting of operatively-integralarms 231 and 239 fulcrumed at 24| on another lever 243 which is itselffulcrumed at 245 on a fixed point. Lever 243 has a short arm portion 241extending beyond the point 24|, and to the end of this arm portion link235 is connected; while link 22| leading from the mechanically operatedlever 2|1 is connected to the end of lever arm 239. A spring 249istensioned between a fixed point and the end of lever arm 239, tendinggenerally tomove the metering valve outward and also to retain camfollower 2 5 in engagement with its cam 2 I3. The lever arm 231 isconnected to the outward portion of the metering valve by a slidablyacting fork structure 25|, or the like, cooperating with an annularchannel on the valve stem.

Apparatus having the essential elements of the invention as embodied inthis' general form (Fig. 3) may be arranged, adapted, or adjusted tooperate in different ways. With the apparatus substantially as shown inthis figure, in accordance with one preferred mode of operation, it maybe assumed that operating conditions especially with regard to loadcharacteristics are such that the throttle position is roughlyproportional to the engine speed. In such case the cam 2|3 operates orpermits movement of the follower 2|5 through link 22| and the levermechanism just above described, so that the metering needle valve 2|| iswithdrawn from its seat as the throttle is opened.

As the engine altitude increases and external air pressure diminishesaccordingly, the aneroid element 223 expands and causes link 235 to pulllever 243 upward; this motion imparted to lever arm 231, the upper endof which has a movementcomponent toward the casing, causes the meteringvalve to be moved inward, towards its seat, reducing the fuel flow. Inthe just-described mode of operation, the stated regulation by theaneroid element 223 is obtained when access to it of external air ispermitted by providing an aperture at any convenient place in thecasing.

If desired, in order partially to assist in fuel adjustment inaccordance with throttle regulation, a connection as by a pipe 253 maybe made from theotherwise closed casing to the manifold or air passageat a point 91 (substantially as in the previous example), andthe amountof regulation obtained may be controlled, or balanced as to its effect,by an opening to external atmosphere, provided, as here specificallyshown, by the pipe 255 leading from aperture 251 to which pipe 253 isconnected, to the main or intake passage at 259; that is, at a pointanterior to the throttle where the pressure is substantially that ofatmosphere. Or,in case a main supercharger is used in the general mannerexplained in connection with Fig. 8, the pressure effect obtained at thepoint 259 will be an atmosphere-plus pressure. In some cases also thepassages, such as pipe 253 through whichcommunication is afforded fromthe manifoldl to the aneroid casing, may be partially obturated as by aplug 26| having an aperture 263 of properly` determined area.

In describing Fig. Lreference was made to a yieldable connection |1 inthe operating linkage for throttle Since the present apparatus dependsto a large extent upon pneumatic action for positioning a fuelregulating element such as the shiftable pump cam 3|, Fig. l, or theneedle valve 2| Fig. 3, and some small amount of time or slight delay isrequired for the pneumatic force to take effect and produce the changein power output intended by the act of throttle adjustment, it issometimes desirable, substantially as shown in Fig. 1, to provide meansfor slightly delaying throttle movement in response to the movement ofthe controlling element, such as rod I3.

Thus, as here shown, the throttle arm 265 has a forked or b-all end 261,or the like, engaging between a collar 269 fixed on the rod I3 and a lugor collar 21| slidable on the rod and urged to engage the lever end by aspring 213 bearing against another collar 215 adjustably fixed on therod. This provides for or permits a slight lag in the throttle movementunder control of a retarder such as a dashpot, as will appear, whe-n therod is moved in a direction to produce throttle opening. When it isdesired to provideI the delayed throttle movement in either direction,an arrangement may be provided such as shown in Fig. wherein the end ofthe throttle arm has a fork 211 with its ends at opposite sides of acollar or stop 219 secured to the controlling rod.

The fork ends are located between the flanges 28| of collars 283, whichare slidable upon the rod and are normally held in engagement with thefixed stop or collar 219 by springs 285 compressed between therespective flanges, and other stops or collars 231 also in fixedposition on the rod. This arrangement provides for a lag in throttlemovement (under control of a dashpot 289 or the like) when the rod 43 ismoved in a direction either to open or to close the throttle. Fig. 1also shows a simplified dashpot arrangement representing broadly anysuitable retarding device to produce the delayed movement of thethrottle, in cooperation with the yieldable operating connection. Thisdashpot 289 has a plunger 29| with :a rod 293 pivotally connected to athrottle arm 295 secured to the throttle shaft and will tend to retardthe throttle movement in either direction, either by pneumatic actionor, if desired, a liquid medium may be supplied to the dashpot, asespecially indicated at 291. Evidently .such throttle retarding meansmay be employed in any f or'ms of the invention, as sufficientlyindicated, for example, in Figs. 2 and 3.

In view of the early-preceding description (re. Fig. l) of one practicalstructure embodying the invention principles as previously discussedwithreference to the diagram, Fig. 4, the following somewhat differentexplanation of the application of that diagram may be understood.Assuming that the lateral diagram of pressures as there shown torepresent the pressures which will be available, operating against thespring 15, Fig. l, to vary the fuel feed, the slope of the line a--a'shows the rate of pressure difference to the air charge when thethrottle is operated; while the slope of the line a-o shows the relationto air charge change caused bychange of altitude. It is desired to bringthese two lines to theV same actual point, as regards their momentagainst the spring 15.

This can be done, first, by making the aneroid element 13 subject toexternal atmospheric pressure, and Calibrating the moment of the diaasealed casing 299 and the diaphragmy 93 is` secured in a mannerto sealan aperture 30| in the main casing and subjected at its inner face tothe same pressure that is applied to the aneroid element. The casing isconnected by a pipe 303 to the intake manifold. substantially as thedistinct chamber 9| of Fig. l is connected to the manifold. The springand lever arrangements may be substantially the same. By this means orarrangement, manifold pressure 'through pipe 303 is applied exteriorlyto the aneroid element and at the same time is interiorly applied to thediaphragm; or, as otherwise stated in this.

case the action of the aneroid under manifold vpressure is assisted bythe action of the diaphragm under the same force. In such case themoment of the diaphragm will be less than in Fig. 1, since the diaphragmand aneroid together operate to reduce the fuel charge as the throttleis closed.

What is claimed is:

1. In combination with an engine having an air supply passage, athrottle therein, and means for supplying fuel into the passage betweenthe throttle and the engine, a pneumatic pressure responsiveinstrumentality subjected to penumatic pressure variations incidenttovariations in operating conditions of the engine and acting to controlthe ratio of the fuel and air mixture substantially in accordance withsuch condition Variations, resilient means acting upon saidinstrumentality in opposition to the action thereon of pneumaticpressure, and means to vary the effect of the pressure responsiveinstrumentality in accordance with variations in operating conditions.

2. In combination with an engine having an air intake and a manuallymovable throttle therein, a fuel pump having a variable stroke forintroducing fuel into the air intake posterior to the throttle, andpneumatic pressure operated means controlling the fuel pump stroke inaccordance with the joint action of the air pressures on opposite sidesof said throttle.

3. In combination with an engine having an air intake and a throttletherefor, means for supplying fuel to the engine, a supercharger forincreasing air flow means responsive to the supercharger pressure forcontrolling the supply of fuel, and means for varying the effect of theresponsive means in accordance with the air intake pressure at a pointposterior of the throttle.

4. In combination with an engine having air and fuel supply means and athrottle controlling Ipressure momentarily existing in the air passageto the engine posterior to the throttle, means actuated by saidinstrumentality tending to controlA the fuel supply in accordance withvariation of such-pressure, and atmospheric pressure actuated means forvarying the effect of the pressure instrumentality.

, 6. In combination with an engine having pressure fuel supply meansincluding a fuel pump having a variable stroke, an air passage to theengine having a manually movable throttle therein, pneumaticpressure'responsive means affected by external atmospheric pressure andby pressure in the air passage posterior lto the throttle and saidpressure responsive means being operatively connected with the fuel pumpfor controlling the fuel pump stroke in conjoint accordance withvariations of said pressures.

7. In combination with an engine having fuel supply means, pneumaticpressure responsive means subjected to atmospheric pressure, otherpneumatic pressure responsive means subjected to manifold pressure, andmeans affected by both said pressure responsive means to regulate thefuel supply.

8. In combination with an engine having fue supply means, pneumaticpressure responsive means subjected to atmospheric pressure, otherpneumatic pressure responsive means subjected to manifold pressure andalso by atmospheric pressure, and means affected by both said pressureresponsive means to regulate the fuel supply.

9. In combination with an engine having air and fuel supply meansincluding a pressure pump and a throttle controlling air supply, apneumatic pressure responsive instrumentality affected simultaneously bymanifold pressure and by external atmospheric pressure and acting toautomatically adjust the fuel supply of the pump.

10. In combination with an engine having air and fuel supply meansincluding a pressure pump and a throttle controlling air supply, apneumatic `effecting a variation of mixture proportions in a part of thefuel adjustment range.

12. In combination with an engine having air and fuel supply means and athrottle controlling air supply, pneumatic pressure responsive meansautomatically tending to adjust the fuel supply whereby to maintain anapproximately uniform mixture proportion, and means acting automaticallyto effect enrichment of the fuel mixture under conditions generallycorresponding to high atmospheric pressure or density and full openthrottle.

13. In combination with an engine having air and fuel supply means and athrottle controlling air supply, a pneumatic pressure responsiveinstrumentality tending to effect fuel supply adjustment in accordancewith atmospheric pressure variations, and mechanical means responsive tothrottle positioning and tending to affect the action of saidinstrumentality.

14. In combination with an engine having air and fuel supply means and athrottle controlling air supply, a pneumatic pressure responsiveinstrumentality tending to effect fuel supply adjustment in accordancewith manifold pressure variations, and mechanical means responsive t0throttle positioning and tending to affect the action of saidinstrumentality. i

15. In combination with an engine having air and fuel supply means and athrottle controlling air supply, a pneumatic pressure responsiveinstrumentality tending to effect fuel supply adjustment in accordancewith atmospheric pressure sitioning and tending to affect the action ofsaid instrumentality.

16. In combination with an engine having air and fuel supply meansincluding 'a fuel pump and a throttle controlling air supply, meansoperated by throttle positioning to adjust the fuel supply, andpneumatic pressure responsive means coacting with the fuel pump toeffect the fuel supply adjustment. l

17. In combination with an engine having air and fuel supply means and athrottle controlling air supply, means operated by throttle positioningto adjust the fuel supply, and pneumatic pressure.

responsive means coacting with the means rst named to effect said supplyadjustment, said pneumatic pressure responsive means being subjected toboth atmospheric pressure and air supply pressure.

18. In combination with an engine having air and fuel supply means and athrottle controlling air supply,'means operated by throttle positioningto adjust the fuel supply, and pneumatic pressure responsive meanscoacting with the means first named to effect said supply adjustment,said pneumatic pressure responsive means being subjected to manifoldpressure.

19. In combination with an engine having air and fuel supply means and athrottle controlling air supply, means operated by throttle positioningto adjust the fuel supply, and pneumatic pressure responsive meanscoacting with the means first named to effect said supply adjustment,said pneumatic pressure responsive means being subjected to manifoldpressure and conjointly to atmospheric pressure.

20. Fuel supply apparatus comprising means for substantiallycontinuously supplying fuel at a substantially high pressure to adelivery point,

and means for varying the amount supplied, said means having twosurfaces subjected to a relatively small pressure diiferential in fuelpressure.

21. Fuel supply apparatus comprising means for substantiallycontinuously supplying fuel at a substantially high pressure to a-delivery point, and means for varying the amount supplied, said meansbeing subjected to fuel pressure and having an input pressure onlymoderately greater than the output pressure.

22. In combination withan engine having air and fuel supply means and athrottle controlling air supply, pneumatic pressure responsive meansautomatically tending to adjust the fuel supply, a spring tending tomove said pressure responsive means in opposition to pneumatic pressureappliedto it, and means to adjust the fuel supply at a different ratethroughout a portion of the expansive range of the pressure responsivemeans.

23. For purposes described, in combination with an element movable toadjust fuel supply, controlling meansv therefor comprising two pneumaticpressure `responsive devices,vand mechanical means operated jointly bysaiddevices an connected to move said element.

24. For purposes described, in combination with an element movable toadjust fuel supply, controlling means therefor comprising two pneumaticpressure responsive devices, and mechanical means operated jointly bysaid devices and connected to move said. element, said mechanical meansincluding means acting in a part of its range of movement to amplify theeffective movement applied to said element.` v

25. For purposes described, in combination with an element movable toadjust fuel supply, controlling means therefor comprising two pneumaticpressure responsive devices, and mechanical means operated jointly bysaid devices and connected to move said element, said mechanical meanscomprising a lever system including a three armed lever, one armoperatively connected to each of said pressure responsive devic-es andthe other arm operatively connected to said element.

26. For purposes described, in combination with an element movable toadjust fuel supply, controlling means therefor comprising two pneumaticpressure responsive devices, and mechanical means operated jointly bysaid devices and connected to move said element, said mechanical meanscomprising a lever system including a three armed lever, one armoperatively connected to each of said pressure responsive devices, and afloating lever mounted on the third arm and itself connected to saidelement.

27. For purposes described, in combination with an element movable toadjust fuel supply, controlling means therefor comprising two pneumaticpressure responsive devices, and mechanical means operated jointly bysaid devices andconnected to move said element, said mechanical meanscomprising a lever system including a three armed lever, one armoperatively connected to each of said pressure responsive devices, and aoating lever mounted on the third arm and. itself connected to, saidelement, and means normally retaining the oating lever in a fixedrelation to the third arm.

28. For purposes described, in combination with an element movable toadjust fuel supply, controlling means therefor comprising two pneumaticpressure responsive devices, and mechanical means operated jointlybysaid devices and connected to move said element, said mechanical meanscomprising a lever system including a three armed lever, one armoperatively connected to each of said pressure responsive devices, and afloating lever mounted on the third arm and itself connected to saidelement, means normally retaining the floating lever in a fixed relationto the third arm, and means acting in an end range of movement ofsaidarm to relatively move the floating lever.

29. A fuel supply system comprising an engine, an air supply passage, athrottle, means for forcing fuel under pressure into the passage betweenthe throttle and the engine, and a pneumatic pressure responsiveinstrumentality subjected to pressure in the air passageanterior to thethrottle and tending to affect the fuel supply substantially inaccordance with air supply pressure variations at that pointl 30. A fuelsupply system comprising an engine, an air supply passage, a throttle,means for introducing fuel into the passage between the throttle and theengine, and a pneumatic pressure responsive instrumentality subjected topressure in the air passage anterior to the throttle and tending toaffect the fuel supply substantially in accordance with air supplypressure variations at that point and another pneumatic pressureresponsive instrumentality subjected to manifold pressure and tending toaffect fuel supply.

31. A fuel supply system comprising an engine, an air supply passage, athrottle, a pump for introducing fuel under pressure into the passagebetween the throttle and the engine, and pneumatic pressure responsivemeans arranged in relation to air charge weight in accordance withpressure variations in the air supply passage anterior to the throttle.

32. A fuel supply system comprising an engine, an air supply passage, athrottle, a pump for introducing fuel under pressure into the passagebetween thethrottle and the engine, and pneumatic pressure responsivemeans arranged to adjust the fuel supply delivered by the pump inrelation to air charge weight in accordance with pressure variations inthe air supply passage anterior to the throttle, and also in accordancewith pressure variations posterior to the throttle.

33. A fuel supply system comprising an engine, an air supply passage, athrottle, means for introducing fuel into the passage between thethrottle and the engine, and pneumatic pressure responsive meansarranged to adjust the fuel supply in relation to air charge weight inaccordance withpressure variations in the air supply passage anterior tothe throttle, and also in accordance with pressure variations posteriorto the throttle, said means including a barometric device subjected topressure in the air supply passage anterior to the throttle and anotherbarometric device subjected to the same pressure and. at the same timeto pressure in the air passage posterior to the throttle.

34. A fuel supply system comprising an engine, an air supply passage, a.throttle, a pump for introducing fuel under pressure into the passagebetween the throttle and the engine, a supercharger discharging into thepassage anterior to the throttle, and a pneumatic-pressure responsiveinstrumentality subjected to pressure in the air passage anterior to thethrottle and tending to aiect `the fuel supply delivered bythe pumpsubstantially in accordance with air supply pressure variations at thatpoint.

35. A fuel supply system comprising an engine, an air supply passage, athrottle, means for introducing fuel into the passage between thethrottle and the engine, a supercharger discharging into the passageanterior to the throttle, and a pneumatic pressure responsiveinstrumentality subjected to pressure in the air passage between thesupercharger and thethrottle and tending to affect the fuel supplysubstantially in accordance with a variable pressure equal to that ofatmosphere plus an increment due to action of the supercharger.

36. A fuel supply systeme-comprising an engine, an air supply passage, athrottle, means for introducing fuel into the passage between thethrottle and the engine, a supercharger discharging into the passageanteriorto the throttle, and a pneumatic pressure responsiveinstrumentality subjected to pressure in the air passage anterior to thethrottle and tending, to affect the fuel supply substantially inaccordance with air supply pressure variations at that point, andanother pneumatic pressure responsive instrumentality subjected tomanifold pressure and tending to affect fuel supply.

37. A fuel supply system comprising an engine, an-air supply passage, athrottle, means for introducing fuel into the passage between thethrottle and the engine, a supercharger discharging into thepassageanterior to the throttle, and

pneumatic pressure responsive means arranged and the throttle.

38. A fuel supply system comprising an engine, an air supply passage, athrottle, means for introducing fuel into the passage between the`throttle and the engine, a supercharger discharging into the passageanterior to the throttle, and pneumatic pressure responsive meansarranged to adjust the fuel supply in relation to air charge weight inaccordance with pressure variations in the vair supply passage betweenthe supercharger and the throttle, and also in accordance with pressurevariations posterior to the throttle.

39. A fuel supply system comprising an engine, an air supply passage, athrottle, means for introducing fuel into the passage between thethrottle and the engine, a supercharger discharging into the passageanterior to the throttle, and pneumatic pressure responsive meansarranged to adjust the fuel supply in relation to air charge weight inaccordance with pressure variations in the air supply passage anteriorto the throttle, and also in accordance with pressure variationsposterior to the throttle, said means including a barometric deviceYsubjected to pressure in the air supply passage between .thesupercharger andthe throttle and another barometric device subjected tothe same pressure and at the same time to pressure in the air passageposterior to the throttle.

40. In combination with an engine having air and fuel supply meansincluding a pressure fuel pump and a conduit having a, throttlecontrolling the air supply, pneumatic pressure responsive means affectedsimultaneously by the air conduit pressure and atmospheric pressure, andsaid pressure responsive means arranged to automatically adjust the fueland air mixture supplied to the" pressure 42. In combination with anengine having an air conduit, a throttle fo'r the conduit, a pressurefuel pump having means for varying the supply of fuel supplied to theengine, means responsive both to conduit pressure posterior to thethrottle and vexternal atmospheric pressure, a vlinkage actuated by saidpressure responsive means to automatically adjust the fuel and airmixture supplied to the engine in accordance with both atmosphericpressure and conduit pressure, and said linkage including a device tovary the controlling effect of the linkage throughout a portion ofmovement range thereof.

43. In combination withl an engine having a conduit for conducting airto the engine, mechani sity of the air between the engine and the con-vduit entrance and in accordance with the densityI of the surroundingatmosphere.

44. In combination with an engine having a conduit for conducting air tothe engine, a reciprocating pump for forcing fuel to the engine, andmeans for controlling the stroke of the fuel pump in accordance with thedensity of the air between the engine and the conduit entrance and inaccordance with the density of the air anterior to the conduit entrance.

45. In combination with an engine having a conduit for conducting air tothe engine, means for controlling the air charge to the engine, anengine driven pump for forcing fuel to the engine, and means forcontrolling the amount vof fuel delivered by the pump in accordance withthe joint actionl of the pressure between the engine and the conduitentrance and the pressure of the air anterior to the conduit entrance.

. 46. In combination with an engine having a conduit for conducting airto the engine, means for controlling the air charge to the engine, anengine driven pump for forcing fuel to the engine,means for controllingthe amount of fuel delivered by the pump in accordance with the jointaction of the pressure of the air between the engine and vthe conduitentrance and the pressure of the air anterior to the conduit entrance,said means including a sealed bellows the expansion and contraction ofwhich is affected by the pressure of the air anterior to the entrance,and a device for controlling the expansion and contraction in accordancewith the pressure of the .air between the engine and the conduitentrance.

47. In combination with an engine, a fuel delivery pump, an air supplyduct having a throttle, manually actuated means for 1 controlling thequantity of the air and fuel mixture, pneumatic means controlled by theabsolute pressure of the air anterior to the throttle arranged tocontrol the relation between the fuel and air charges, and otherpneumatic means associated with the first pneumatic means and responsiveto the difference in pressures on opposite sides of the throttle forfurther controlling the relation of the air and fuel charges. i

48. In combination with an engine, a fuel delivery pump, an air supplyduct having a throttle, manually actuated means for controlling thequantity of the air and fuel mixture, pneumatic means responsive to theabsolute pressure in the duct controlling the relation of the f uel andair charges, and other pneumatic means associated with the firstpneumatic means and responsive to the difference in air pressure onopposite sides of the throttle for further controlling the relation ofthe fuel and air charges.

FRANK C. MOCK.

